This script is based off a script from crunchbang linux a distribution mostly for laptops, and turned into an init-level script for Debian. It sets a few options that will make your server consume less power. The idea stems from sparing battery power, but the same can be applied to desktop servers since most of the time a lot of the hardware (such as USB ports) lay dormant. The idea is not as much to conserve power, than to increase the longevity of the server.

This benefits hardware in many ways:

• wear-and-tear, while hardware devices are active and electricity flows through them, the electricity slowly tears at the hardware - this can even be observed on old motherboards.
• less interrupts, as long as the hardware lays dormant, the kernel does not have to bother with that hardware and it can lay in a dormant state.
• performance, based on the former, as long as the CPU is not busy managing hardware that is not active nor used, it can focus on other tasks.
• heat, active hardware that is never used can increase the heat within the casing, as a consequence it can also make the fans run faster to compensate and we're back at wear-and-tear.

As an optimization technique, power-management can be greatly beneficial to the longevity of the server.

• For servers, a conservative or ondemand CPU frequency governor can be used that will take care to change the frequencies depending on the work-load that the CPU has to accomplish.
• irqbalance can be used to balance interrupts across processors.
• adding relatime to the /etc/fstab options, on the most accessed filesystems can reduce the number of accesses to the harddrives.

A script that will batch-apply settings on restart can be found in the script collection.